On 2019-Nov-22, Michael Paquier wrote: > On Fri, Nov 22, 2019 at 10:35:51AM -0300, Alvaro Herrera wrote: > > FWIW I think the new code is buggy because it doesn't seem to be setting > > ws_off, so I suppose the optimization in ReadPageInternal to skip > > reading the page when it's already the page we have is not hit, except > > for the first page in the segment. I didn't verify this, just my > > impression while reading the code. > > FWIW, this matches with my impression here, third paragraph: > https://www.postgresql.org/message-id/20191120083802.gb47...@paquier.xyz
Ah, right. I was wondering if we shouldn't do away with the concept of "offset" as such, since the offset there is always forcibly set to the start of a page. Why don't we count page numbers instead? It seems like the interface is confusingly generic (measure in bytes) yet not offer any extra functionality that could not be obtained with a simpler struct repr (measure in pages). But then that's not something that we need to change in this patch. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
